JP2015034783A - Sensor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To disclose a technology capable of suppressing a contact of a foreign matter with an electrode pair.SOLUTION: A sensor device 2 includes: a jet pump 44 for making a reserve cup 20 discharge fuel; and an electrode pair placed in a direction in which fuel is discharged from a discharge port of the jet pump 44. The electrode pair is placed on a second plate 66 of a substrate 62. In the electrode pair an electrostatic capacitance varies depending on liquid quality of the fuel.

Description

  In this specification, the sensor apparatus for detecting the liquid quality of the fuel stored in a fuel tank is indicated.

  Patent Document 1 discloses a liquid level measuring device for measuring a liquid level of fuel. The liquid level measuring device includes a measurement electrode portion that extends from the bottom of the sub tank so as to protrude above the sub tank, and a reference electrode portion that is set inside the sub tank. The liquid level measuring device measures the liquid level of the fuel in the fuel tank using the measurement electrode unit and the reference electrode unit.

JP-A-2-87022

  There may be foreign matters other than fuel around the electrode. In particular, foreign matter may accumulate on the bottom of the sub-tank or the like. When the foreign matter in the fuel tank comes into contact with the electrode pair, the capacitance of the electrode pair varies depending on the foreign matter. Moreover, when a foreign material contacts both two electrodes of an electrode pair, an electrode pair may be conducted. As a result, even if the capacitance of the electrode pair is used, the fuel level in the fuel tank may not be measured appropriately. In this specification, the technique which suppresses that a foreign material contacts an electrode pair is disclosed.

  In this specification, the sensor apparatus for detecting the liquid quality of the fuel stored in a fuel tank is indicated. The sensor device includes a jet pump and a first electrode pair. The jet pump is configured to discharge fuel to the reserve cup. The first electrode pair is disposed in the direction in which the fuel discharged from the jet pump flows. The capacitance of the first electrode pair changes according to the liquid quality of the fuel.

  According to this structure, it can suppress that the foreign material in a fuel adheres to the 1st electrode pair with the flow of the fuel discharged from a jet pump. As a result, it is possible to suppress a change in the capacitance of the first electrode pair due to the adhesion of foreign matter.

The structure around the fuel tank of the first embodiment is shown. The structure of the electrode pair arrange | positioned at the 1st flat plate of the board | substrate of 1st Example is shown. The structure of the electrode pair arrange | positioned at the 2nd flat plate of the board | substrate of 1st Example is shown. The figure which looked at the circumference of the sensor main part of the 1st example from the upper part is shown. The structure around the fuel tank of the second embodiment is shown. The figure which looked at the case which accommodates the sensor main body of 2nd Example from upper direction is shown.

  The main features of the embodiments described below are listed. The technical elements described below are independent technical elements and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Absent.

(Feature 1) The sensor device may further include a reserve cup. The first electrode pair may be disposed at the bottom of the reserve cup.

  When the fuel pump is stopped, stirring of the fuel in the reserve cup is stopped. As a result, when the fuel contains water, the water in the fuel accumulates at the bottom of the reserve cup. According to this configuration, the first electrode pair can be brought into contact with water accumulated at the bottom of the reserve cup. Since the dielectric constant of the fuel is different from the dielectric constant of water, the capacitance of the first electrode pair changes depending on the presence or absence of contact with water. For this reason, the presence or absence of water separated from the fuel can be detected using the first electrode pair while the fuel pump is stopped.

(Characteristic 2) The sensor device may further include a bubble-proof wall disposed above the first electrode pair and at a position closer to the jet pump than the first electrode pair.

  In this configuration, the bubbles contained in the fuel discharged from the jet pump collide with the antifoam wall and are guided. According to this configuration, bubbles contained in the fuel discharged from the jet pump can be suppressed from flowing toward the first electrode pair. Thereby, it can suppress that a bubble adheres to the 1st electrode pair. As a result, it is possible to suppress the capacitance of the first electrode pair from changing due to bubbles adhering to the first electrode pair.

(Feature 3) The sensor device may further include a case for housing the first electrode pair. The case may be provided with a through hole through which fuel passes.

  According to this configuration, the case can suppress foreign matters and bubbles from adhering to the first electrode pair.

(Feature 4) The case may be made of a conductive material.

  According to this configuration, the case exhibits the function of an electromagnetic shield by grounding the case. As a result, generation of stray capacitance can be suppressed.

(Feature 5) The sensor device may include a second electrode pair and a control unit. The second electrode pair may be disposed outside the reserve cup and inside the fuel tank. The capacitance of the second electrode pair may change according to the liquid quality of the fuel and the liquid level in the fuel tank. The control unit may calculate the liquid level in the fuel tank using the first electrode pair and the second electrode pair.

  According to this configuration, it is possible to appropriately detect the liquid level of the fuel in the fuel tank in consideration of the liquid quality of the fuel.

(Feature 6)
The sensor device may further include a substrate on which the first electrode pair and the second electrode pair are disposed.

  According to this structure, the assembly | attachment property of an electrode pair can be improved compared with the structure where the 1st electrode pair and the 2nd electrode pair are arrange | positioned on a different board | substrate.

(Feature 7) The sensor device may further include a third electrode pair arranged outside the reserve cup and in the fuel tank. The capacitance of the third electrode pair may change according to the liquid quality of the fuel. The control unit may specify a comparison result between a value related to the capacitance of the first electrode pair and a value related to the capacitance of the third electrode pair.

  Both the value relating to the capacitance of the first electrode pair and the value relating to the capacitance of the third electrode pair change according to the liquid quality of the fuel. Therefore, the comparison result between the value related to the capacitance of the first electrode pair and the value related to the capacitance of the third electrode pair is generally substantially constant. In other words, when the comparison result is different from normal, there is a possibility that an abnormality such as disconnection has occurred in the sensor device. According to this configuration, an abnormality such as disconnection can be detected in the sensor device.

(First embodiment)
The fuel supply unit 1 of this embodiment is mounted on an automobile and supplies fuel to an engine (not shown). The fuel supply unit 1 includes a fuel tank 10, a fuel pump unit 30, and a sensor device 2. The fuel tank 10 stores a mixed fuel of gasoline and ethanol. Fuel is supplied to the fuel tank 10 from an oil supply port (not shown).

  The fuel pump unit 30 includes a pump body 34, a low pressure filter 32, a high pressure filter 36, a reserve cup 20, a pressure regulator 42, and a discharge port 12. The pump body 34, the low pressure filter 32, the high pressure filter 36, the reserve cup 20, and the pressure regulator 42 are disposed in the fuel tank 10. The pump main body 34 sucks the fuel in the fuel tank 10 from the suction port 34 a of the pump main body 34 via the low pressure filter 32, and raises the pressure in the pump main body 34. The pump body 34 discharges the pressurized fuel from the discharge port 34 b of the pump body 34 into the case 36 a of the high-pressure filter 36. Although simplified in FIG. 1, the case 36 a is arranged so as to make a round in the circumferential direction of the pump body 34. The fuel flowing into the case 36 a is filtered by the filter member and sent out to the pipe 94. A pressure regulator 42 is connected to the pipe 94. The pressure regulator 42 releases excess fuel in the pipe 94 to the fuel tank 10 when the pressure of the fuel in the pressure regulator 42 exceeds a predetermined pressure. Thereby, the pressure of the fuel in the pipe 94 is adjusted to a constant pressure. The fuel in the fuel tank 10 is adjusted to a constant pressure by the pump body 34 and the pressure regulator 42 and is pumped from the discharge port 12 to the engine (not shown). The case 36 a communicates the discharge port 34 b of the pump body 34 and the pipe 94. The pipe 94 communicates the discharge port 34 b of the pump body 34 and the discharge port 12.

  The pump body 34 includes a vapor jet 38. The vapor jet 38 communicates the fuel flow path in the pump main body 34 and the fuel tank 10 outside the pump main body 34. The vapor jet 38 is a communication path for discharging fuel bubbles in the pump body 34 to the outside of the pump body 34. The fuel pressurized by the pump main body 34 is discharged from the vapor jet 38 to the discharge pipe 52.

  The low pressure filter 32, the pump body 34, and the high pressure filter 36 are disposed in the reserve cup 20. The reserve cup 20 is fixed to the set plate 14 of the fuel tank 10 by a column 22. A jet pump 44 (see FIG. 4) is disposed at the bottom of the reserve cup 20. The jet pump 44 sends fuel outside the reserve cup 20 into the reserve cup 20 using the flow rate of the fuel released from the vapor jet 38. For example, it has a venturi structure, and when the fuel released from the vapor jet 38 passes through the venturi, the fuel outside the reserve cup 20 is sucked into the jet pump 44 and the fuel sucked from outside the reserve cup 20 is vapor jet. The fuel discharged from the fuel 38 is fed into the reserve cup 20. When the reserve cup 20 and the jet pump 44 are provided, the liquid level around the pump body 34 can be kept high even when the fuel remaining in the fuel tank 10 is small. In the modification, the jet pump 44 may use the flow rate of the fuel released from the pressure regulator 42 or the fuel in the pipe branched from the pipe 94.

  The sensor device 2 includes a control device 80, a sensor main body 60, cases 70 and 74, and a bubble-proof wall 75. The sensor body 60 includes a substrate 62, electrode pairs 81 and 83 (see FIG. 2), an electrode pair 67 (see FIG. 3), and a temperature detection element 65 (see FIG. 3).

  The substrate 62 includes a rectangular first flat plate 82 and a rectangular second flat plate 66. The first flat plate 82 and the second flat plate 66 are integrally formed. The first flat plate 82 extends in the height direction of the fuel tank 10 along the outer peripheral surface of the reserve cup 20. The second flat plate 66 is connected to the lower end of the first flat plate 82. The second flat plate 66 passes through the reserve cup 20 and is disposed in the reserve cup 20.

  The first flat plate 82 is accommodated in the case 70. The case 70 communicates with the discharge pipe 52. For this reason, part of the fuel released from the vapor jet 38 is released into the case 70. Near the bottom of the case 70, a communication hole 78 that communicates the inside and outside of the case 70 is formed. As a result, the fuel level in the case 70 matches the fuel level in the fuel tank 10.

  As shown in FIG. 2, electrode pairs 81 and 83 are arranged on the surface of the first flat plate 82, that is, the surface opposite to the surface facing the outer peripheral surface of the reserve cup 20. The electrode pair 81 includes two electrodes 84 and 85. Each of the electrodes 84 and 85 is made of a thin film conductive material (for example, gold or copper alloy). The electrodes 84 and 85 are disposed on the first flat plate 82 so as to face each other. Each of the electrodes 84 and 85 is formed in a comb shape and extends in the longitudinal direction of the first flat plate 82 (that is, the depth direction of the fuel tank 10). In the electrode 84, a plurality (17 in FIG. 2) of horizontal portions 84 a are electrically connected by vertical portions 84 b extending in the longitudinal direction of the first flat plate 82. The same applies to the horizontal portion 85a and the vertical portion 85b of the electrode 85. The plurality of horizontal portions 84 a and the plurality of horizontal portions 85 a are alternately arranged in the longitudinal direction of the first flat plate 82.

  The electrode pair 83 is disposed closer to the bottom surface side of the fuel tank 10 than the electrode pair 81. The electrode pair 83 includes two electrodes 86 and 87. Each of the electrodes 86 and 87 is made of a thin film conductive material (for example, gold or copper alloy). The electrodes 86 and 87 are disposed on the first flat plate 82 so as to face each other. Each electrode 86, 87 is formed in a comb shape. In the electrode 86, a plurality of (three in FIG. 2) horizontal portions 86a are electrically connected by a vertical portion 84b. In the electrode 87, a plurality (two in FIG. 2) of horizontal portions 87 a are electrically connected by vertical portions 87 b extending in the longitudinal direction of the first flat plate 82. The plurality of horizontal portions 86 a and the plurality of horizontal portions 87 a are alternately arranged in the longitudinal direction of the first flat plate 82.

  As shown in FIG. 1, the second flat plate 66 is disposed in parallel to the bottom surface of the reserve cup 20. The lower surface of the second flat plate 66 is in contact with the bottom surface of the reserve cup 20. As shown in FIG. 3, an electrode pair 67 and a temperature detection element 65 are disposed on the upper surface of the second flat plate 66. The electrode pair 67 includes two electrodes 68 and 69. Each of the electrodes 68 and 69 is made of a thin film conductive material (for example, gold or copper alloy). The electrodes 68 and 69 are disposed on the second flat plate 66 so as to face each other. Each electrode 68, 69 is formed in a comb shape. In the electrode 68, a plurality (four in FIG. 2) of horizontal portions 68 a are electrically connected by vertical portions 68 b extending in the longitudinal direction of the second flat plate 66. The same applies to the horizontal portion 69a and the vertical portion 69b of the electrode 69. The plurality of horizontal portions 68 a and the plurality of horizontal portions 69 a are alternately arranged in the longitudinal direction of the second flat plate 66. Each electrode 68, 69 is connected to the control device 80. Note that the capacitance of the electrode pair 83 and the capacitance of the electrode pair 67 match when used in the same environment and conditions. The temperature detection element 65 is an element whose resistance value varies in correlation with the temperature of the temperature detection element 65.

  As shown in FIG. 4, the second flat plate 66 is covered with a case 74 in the reserve cup 20. The second flat plate 66 is accommodated in a space defined by the case 74 and the reserve cup 20. The case 74 is made of a conductive material such as metal. The case 74 has a plurality of through holes 74 a that penetrate the case 74.

  The case 74 is disposed in front of the discharge port 44 a of the jet pump 44. When viewed from above, the anti-foam wall 75 is disposed between the case 74 and the discharge port 44a. The bubble-proof wall 75 is disposed above the discharge port 44 a and the electrode pair 67.

  The control device 80 is connected to a battery not shown. The control device 80 is electrically connected to the electrode pairs 67, 81, 83 and the temperature detection element 65 via the conductive wire 54. The control device 80 converts the power supplied from the battery into a signal (alternating current) having a predetermined frequency (for example, 10 Hz to 3 MHz), and supplies the signal to each of the electrodes 68, 85, and 87. The control device 80 further supplies a direct current voltage to the temperature detection element 65 using electric power supplied from the battery. The control device 80 grounds the electrodes 69, 84, 86 and the case 74.

  Next, the operation of the fuel supply unit 1 will be described. For example, when the driver operates an ignition switch to start the automobile, the fuel supply unit 1 is driven. When the fuel supply unit 1 is driven, the pump body 34 is driven, and the fuel in the reserve cup 20 passes through the low pressure filter 32 and is sucked into the pump body 34 from the suction port 34a. The fuel in the pump body 34 is boosted by the impeller in the pump body 34. Part of the fuel pressurized by the impeller is discharged from the vapor jet 38 to the discharge pipe 52 together with bubbles in the fuel. Part of the fuel discharged from the vapor jet 38 passes through the discharge pipe 52 and is discharged into the case 70.

  Further, another part of the fuel discharged from the vapor jet 38 flows into the jet pump 44. The jet pump 44 sucks the fuel outside the reserve cup 20 into the jet pump 44, and the fuel sucked from the outside of the reserve cup 20 is discharged into the reserve cup 20 from the discharge port 44a together with the fuel discharged from the vapor jet 38. . As a result, fuel having a relatively high pressure is discharged from the discharge port 44a. The fuel discharged from the discharge port 44a flows toward the case 74. The fuel flows through the case 74 through the through hole 74 a of the case 74 and is discharged out of the case 74.

  The other part of the fuel pressurized by the impeller is discharged from the discharge port 34b into the case 36a of the high-pressure filter 36. The fuel in the case 36 a is filtered by the filter member of the high-pressure filter 36 and supplied to the engine from the discharge port 12 through the pipe 94.

  During the driving of the pump body 34, the control device 80 detects the ethanol concentration contained in the fuel in the fuel tank 10 using the temperature detection element 65 and the electrode pair 67. Further, the control device 80 measures the liquid level of the fuel in the fuel tank 10 using the electrode pairs 67 and 83. Further, the control device 80 uses the electrode pairs 67 and 83 to detect whether or not an abnormality has occurred in the sensor device 2. The control device 80 repeatedly executes the above processing until the automobile engine is stopped.

  Specifically, first, the control device 80 supplies a DC voltage to the temperature detection element 65 and detects the temperature of the temperature detection element 65 from the current value of the temperature detection element 65. Since the temperature detection element 65 is entirely immersed in the fuel, the temperature of the temperature detection element 65 is substantially the same as the temperature of the fuel in the fuel tank 10. The control device 80 stores a mathematical expression indicating a correlation between the resistance value of the temperature detection element 65 and the temperature of the temperature detection element 65. The resistance value of the temperature detection element 65 is calculated from the current value of the temperature detection element 65, and the temperature value of the temperature detection element 65, that is, the temperature of the fuel is detected using the resistance value of the temperature detection element 65 and a mathematical expression.

  Next, the control device 80 supplies an AC voltage to the electrode 68 of the electrode pair 67 and specifies the capacitance of the electrode pair 67. The electrode pair 67 is entirely immersed in the fuel. For this reason, the capacitance of the electrode pair 67 varies in correlation with the dielectric constant of the fuel, but does not vary depending on the liquid level in the fuel tank 10. The dielectric constant of the fuel varies with the ethanol concentration and temperature. The control device 80 is mounted with a circuit for converting the measured capacitance of the electrode pair 67 into a fuel dielectric constant. In addition, the control device 80 stores a database indicating the relationship between the dielectric constant of the fuel specified by experiment or analysis in advance, the detected temperature of the fuel, and the ethanol concentration in the fuel. The control device 80 refers to the database to detect the ethanol concentration in the fuel from the fuel dielectric constant and the fuel temperature. The control device 80 outputs the detected ethanol concentration to an ECU (abbreviation of engine control unit) not shown. The ECU adjusts the amount of fuel supplied to the engine according to the ethanol concentration in the fuel.

  Next, the control device 80 measures the capacitance of the electrode pair 81. The fuel level in the case 70 matches the fuel level in the fuel tank 10 outside the case 70. Since the dielectric constants of the fuel and the gas in the fuel tank 10 are different, the capacitance of the electrode pair 81 varies in correlation with the fuel level of the case 70. Furthermore, the capacitance of the electrode pair 81 varies in correlation with the dielectric constant of the fuel. The control device 80 is mounted with a circuit for converting the capacitance of the electrode pairs 81 and 67 into the fuel level. The control device 80 outputs the specified fuel level to the display device of the automobile. According to this configuration, the liquid level of the fuel can be detected using the sensor device 2. In addition, the influence of the dielectric constant of the fuel on the capacitance of the electrode pair 81 can be suppressed by using the capacitance of the electrode pair 67. Thereby, the fuel level can be detected more accurately.

  Subsequently, the control device 80 measures the capacitance of the electrode pair 83. Since the electrode pair 83 is disposed below the electrode pair 81, the electrode pair 83 is generally immersed in fuel as a whole. For this reason, the capacitance of the electrode pair 83 varies in correlation with the dielectric constant of the fuel, but does not vary depending on the level of the liquid level in the fuel tank 10. In addition, the capacitance of the electrode pair 83 is generally substantially the same as the capacitance of the electrode pair 67. The control device 80 compares the capacitance of the electrode pair 67 with the capacitance of the electrode pair 83. When the difference between the capacitance of the electrode pair 67 and the capacitance of the electrode pair 83 exceeds a predetermined numerical range, the control device 80 indicates that there is an abnormality in the sensor device 2 in the display device of the automobile. The information shown is output. Thus, the driver can know that an abnormality such as a disconnection has occurred in the sensor device 2.

  The control device 80 further supplies an AC voltage to the electrode 68 of the electrode pair 67 while the pump body 34 is stopped, and measures the capacitance of the electrode pair 67. The fuel in the fuel tank 10 may contain water. Since the specific gravity of water is greater than that of fuel, the water separates from the fuel in the fuel tank 10 while the pump body 34 is stopped, that is, while the fuel is not being stirred, and the bottom of the fuel tank 10 and It collects near the bottom of the reserve cup 20. The electrode pair 67 is disposed near the bottom of the reserve cup 20. That is, when moisture is contained in the reserve cup 20, moisture exists around the electrode pair 67 while the pump body 34 is stopped. As a result, the capacitance of the electrode pair 67 is greatly different from that in the case where fuel exists around the electrode pair 67. When the capacitance of the electrode pair 67 exceeds a predetermined numerical range, the control device 80 outputs information indicating that water is accumulated in the fuel tank 10 to the display device of the automobile. To do. Thus, the driver can know that water is accumulated in the fuel tank 10.

  In the sensor device 2, the electrode pair 67 is arranged in the direction in which the fuel discharged from the discharge port 44 a of the jet pump 44 flows. As a result, when foreign matter is attached to the electrode pair 67, the foreign matter is removed by the fuel discharged from the discharge port 44a. According to this configuration, it is possible to suppress foreign matters in the fuel from adhering to the electrode pair 67 due to the flow of fuel discharged from the jet pump 44. As a result, it is possible to prevent the capacitance of the electrode pair 67 from changing due to foreign matter adhering to the electrode pair 67.

  The electrode pair 67 can detect the fuel discharged from the jet pump 44, that is, the same fuel as the fuel supplied to the engine.

  The case 74 has conductivity and is grounded. For this reason, the case 74 functions as an electromagnetic shield. As a result, generation of stray capacitance by the electrode pair 67 can be suppressed.

  Each of the electrode pairs 67, 81, 83 is disposed on one substrate 62. According to this configuration, the assemblability of the electrode pairs 67, 81, 83 can be improved as compared with the configuration in which the electrode pairs 67, 81, 83 are arranged on separate substrates.

  The fuel discharged from the jet pump 44 may contain bubbles. In the sensor device 2, the anti-foam wall 75 is disposed between the case 74 and the discharge port 44 a. Bubbles contained in the fuel discharged from the jet pump 44 collide with the anti-foam wall 75 and are guided. According to this configuration, bubbles contained in the fuel discharged from the jet pump 44 can be prevented from flowing toward the electrode pair 67. Thereby, it can suppress that a bubble adheres to the electrode pair 67. FIG. As a result, it is possible to prevent the capacitance of the electrode pair 67 from changing due to bubbles adhering to the electrode pair 67.

(Second embodiment)
Differences from the first embodiment will be described. As shown in FIG. 5, the sensor device 2 of the second embodiment includes a sensor main body 160 instead of the sensor main body 60. The sensor main body 160 includes a substrate 162, an electrode pair 67, a temperature detection element 65, and a terminal 160a. The substrate 162 has a configuration similar to that of the second flat plate 66. Terminal 160 a electrically connects electrode pair 67 and temperature detection element 65 to conductive wire 54.

  The substrate 162 is surrounded by the case 174. The case 174 is made of a conductive material such as metal. The case 174 is fixed to the bottom surface of the reserve cup 20. As shown in FIG. 6, the case 174 includes an upper wall 174a and two side walls 174b. Each side wall 174 b is a rectangular flat plate protruding from the bottom surface of the reserve cup 20. Each side wall 174 b is also in contact with the side surface of the reserve cup 20. The two side walls 174b are arranged in parallel. A jet pump 44 is disposed between the side walls 174b. An upper wall 174a is disposed at the upper ends of the two side walls 174b. The upper wall 174 a is disposed away from the side surface of the reserve cup 20. A foam-proof wall 175 is disposed above the end of the upper wall 174a on the side surface side of the reserve cup 20.

  The substrate 162 is disposed between the side walls 174b. The substrate 162 is fixed in the reserve cup 20 by being fixed to the case 174. According to this configuration, the substrate 162 can be appropriately disposed on the reserve cup 20. The substrate 162 is covered with the upper wall 174a.

  According to this configuration, similarly to the first embodiment, the substrate 162 is arranged in the direction in which the fuel discharged from the jet pump 44 flows. According to this configuration, it is possible to suppress foreign matters in the fuel from adhering to the electrode pair 67 due to the flow of fuel discharged from the jet pump 44. As a result, it is possible to prevent the capacitance of the electrode pair 67 from changing due to foreign matter adhering to the electrode pair 67.

  Further, as in the first embodiment, it is possible to suppress bubbles from adhering to the electrode pair 67. Furthermore, the case 174 can suppress the generation of stray capacitance. Further, the water in the fuel tank 10 can be detected using the electrode pair 67.

  In the modification, the sensor device 2 of the second embodiment may include a sensor having the same configuration as the second flat plate 82 and the electrode pairs 81 and 83.

  As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

(Modification)
(1) In the above embodiment, the sensor device 2 detects the ethanol concentration in the fuel using the electrode pair 67. However, the sensor device 2 may detect the degree of fuel deterioration (for example, the degree of fuel oxidation). In the present modification, the degree of deterioration is an example of “liquid quality”.

(2) The shape of each electrode pair 67, 81, 83 is not limited to the above shape. For example, at least one electrode of each electrode pair may have a flat plate shape, a column shape, or a polyhedral shape.

(3) In each of the embodiments described above, the control device 80 provides information indicating that the sensor device 2 has an abnormality as a result of comparing the capacitance between the electrode pair 67 and the electrode pair 83 in the display device of the automobile. Output. However, the control device 80, as a comparison result of the capacitance between the electrode pair 67 and the electrode pair 83, information indicating the degree of difference in capacitance (the difference is relatively large or the difference is relatively small). May be output to a display device of an automobile. In addition, the control device 80 may output information obtained from the comparison result to the audio output device. The voice output device may output information obtained from the comparison result by voice. In general, the control device 80 may output the comparison result of capacitance between the electrode pair 67 and the electrode pair 83 or information obtained from the comparison result to a device that uses the result or information. .

(4) In each of the above embodiments, the electrode pair 67 is disposed in front of the discharge port 44 a of the jet pump 44. However, the electrode pair 67 may not be disposed in front of the discharge port 44a. For example, the sensor device 2 may include a barrier for changing the flow direction of the fuel discharged from the discharge port 44a. The electrode pair 67 may be arranged in the fuel flow direction changed by the barrier. This modification is also included in the configuration in which the electrode pair 67 is “arranged in the direction in which the fuel discharged from the jet pump flows”.

(5) In the first embodiment, the case 74 includes a plurality of through holes 74a. However, the case 74 may be made of a mesh material or non-woven fabric through which fuel can pass.

(6) In the first embodiment, the fuel level is detected using the electrode pairs 67 and 81. However, the fuel level may be detected using the electrode pairs 83 and 81.

  The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

2: Sensor device 10: Fuel tank 20: Reserve cup 30: Fuel pump unit 38: Vapor jet 44: Jet pump 44a: Discharge port 60: Sensor body 62: Substrate 67, 81, 83: Electrode pair 74: Case 74a: Through Hole 75: Antifoam wall 80: Control device

Claims (8)

A sensor device for detecting liquid quality of fuel stored in a fuel tank,
A jet pump for discharging fuel to the reserve cup;
A sensor device comprising: a first electrode pair disposed in a direction in which fuel discharged from a jet pump flows, wherein the first electrode pair changes in capacitance according to the liquid quality of the fuel. A reserve cup,
The sensor device according to claim 1, wherein the first electrode pair is disposed at a bottom portion of the reserve cup.   The sensor device according to claim 1, further comprising a foam-proof wall disposed above the first electrode pair and at a position closer to the jet pump than the first electrode pair.   The sensor device according to any one of claims 1 to 3, further comprising a case that accommodates the first electrode pair and includes a through hole for allowing fuel to pass therethrough.   The sensor device according to claim 4, wherein the case is made of a conductive material. A second electrode pair disposed outside the reserve cup and disposed in the fuel tank, the second electrode pair having a capacitance that varies according to a liquid quality of the fuel and a liquid level in the fuel tank;
The sensor device according to any one of claims 1 to 5, further comprising: a control unit that calculates a liquid level in the fuel tank using the first electrode pair and the second electrode pair.   The sensor device according to claim 6, further comprising a substrate on which the first electrode pair and the second electrode pair are arranged. A third electrode pair arranged outside the reserve cup and disposed in the fuel tank, wherein the capacitance of the third electrode pair varies according to the liquid quality of the fuel;
The sensor device according to claim 6 or 7, wherein the control unit specifies a comparison result between a value related to the capacitance of the first electrode pair and a value related to the capacitance of the third electrode pair.

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